


sweetest submission (drinking it in)

by brightlyburning



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Bottom Dimitri Alexandre Blaiddyd, Dragons, Nonbinary My Unit | Byleth, Other, Overstimulation, Top My Unit | Byleth
Language: English
Status: Completed
Published: 2020-10-31
Updated: 2020-10-31
Packaged: 2021-03-09 01:42:35
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,687
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27296608
Author URL: https://archiveofourown.org/users/brightlyburning/pseuds/brightlyburning
Summary: “I fail to see,” Dimitri said, somehow pleased with himself at how steady his voice was, “how kidnapping me grants any of my wishes.”‘You stood at your window and gazed upon the Fell Star,’ said the dragon, ‘with a satisfied lover in your bed, and yet you- ’ it continued relentlessly as Dimitri choked on an indrawn breath, ‘you were unsatisfied. Aching with it.’What-?‘Aching,’ said Byleth, and its voice grew low with terrible satisfaction, ‘for you wish, more than anything, to be pleasured until it overwhelms you, until you are no king at all, until all the cares in your mind have been driven away. To be held down and made to take it, and yet every human lover Fodlan offers you can never have hope of pinning you. Can never match your need.’(For FE3H Monsterfucking Week, prompts overstimulation and dragons.)
Relationships: Dimitri Alexandre Blaiddyd/My Unit | Byleth
Comments: 18
Kudos: 167
Collections: FE3H Monsterfucking Weekend 2020





	sweetest submission (drinking it in)

_'Well_ ,' Dimitri thought as the ground fell away beneath him, ' _this is a disappointing way to go._ ' Far below, Felix and Sylvain's panicked faces dwindled into pale dots, then disappeared between the trees. Dimitri's horse, its stirrups flapping, whirled and bolted into the forest. Pity. He'd liked that horse, and it wasn't easy to find one that could bear his weight. A part of him scolded himself for not bringing a weapon besides his hunting bow, sadly abandoned far below, but really, who expected kidnapping from the sky on a hunting trip?

Dimitri twisted in the beast's grip, its claws tightening onto his shoulders, and craned his head back to try and get a better view, even as the wind tore at his clothes and made his eye water. Four legs, two wings, great curving horns arching up from the crown of its reptilian skull: definitely a dragon, even though they'd supposedly died off in ages past. Its scales shone in the sunlight, a deep green-blue along its spine that faded into a pale luminescence, the color of starlight, on its limbs and the great sails of its wings. The beating of its wings drowned out all noise, so it seemed pointless to try and communicate while it labored higher into the chill air, Dimitri clutched fast in its claws.

Dragons didn't eat people, from what little Dimitri recalled, but what business could a creature like this could have with the newly-crowned king of Faerghus?

The dragon, having reached whatever height it wanted, stopped flapping its wings and began to glide, which Dimitri's stomach was thankful for; his breakfast, light as it had been, didn't sit easy while he was being jerked further into the sky with each wingbeat. Faerghus sprawled beneath him: the dark green waves of the forest, broken here and there by the winding pale serpents of roads, and ahead, a low range of snowcapped mountains.

The mountains grew larger as the dragon descended toward them, then past the first rank of small foothills, into the valleys between the peaks where all was gray stone and melting spring snow. One clawed hand loosened its terrible grip on his shoulders, and before Dimitri could do anything, slipped down his side, claws prickling through his shirt, and scooped up his knees so he was cradled to its chest. 

This close, the unreality of the beast pressed even closer upon him: the strange scent of it, petrichor and acrid; the faint twisting ropes of light beneath its scales; the terrible delicacy of how carefully it held him close to the great bellows of its ribs. Its wings began to beat again, frantic this time, holding itself aloft while its tail and rear limbs descended, searching, and then, in a cloud of snow and dust, it settled onto something. 

Dimitri twisted enough to catch a glimpse of a small outcropping of stone, fringed with great icicles and a few wind-gnarled shrubs, before the dragon bore him inside a cave mouth. Its massive head ducked as it entered, and the darkness that closed upon them broke only at the glow of its eyes and scales. It carried him with surprising skill for a beast that looked so ungainly, down the eerily smooth passage and around a turn, then came to a halt. Its forelimbs sank, claws loosening, and it set Dimitri upright upon the stone, then sat down, forelimbs together, hindlimbs tucked neatly beneath itself. Almost catlike, and wasn't that a ridiculous thought?

Dimitri backed away, folding his arms close about himself to ward off the chill, and kept his gaze on the beast, unwilling to turn. Goddess, the entire palace must be frantic by now- what could this creature even want with him? 

The dragon's eyes reflected him, his hair windblown, his mouth red and windbitten, his clothes half-torn from its claws. Yet it said nothing, only tilted its head, horns barely clearing the cavern ceiling, and opened its terrible jaws, lined with teeth that glittered in its own light, to breathe out a long exhale, perfumed with a strange scent - lightning, or the aftermath of it. Oil lamps burst to roaring life around the perimeter of the cavern, and only Dimitri's determination to show no weakness kept him from jumping out of his skin. He took another step back, tightening his hands into fists where he’d tucked them into his armpits to shake off the chill. Not that it would matter much if the dragon decided to do... whatever it intended, but at the moment it seemed prudent. 

The cavern, illuminated in the warm glow of the lamps, had him biting back an incredulous sound. An opulent tapestry hung over the exit to the outside, stirring in the faint wind blowing down the passage. The lamps themselves were hewn into the very rock in little pools of oil with wicks floating atop them, and mismatched carpets covered the inhumanly smooth floor of the cavern. No chisel marks anywhere, or a single rough patch upon what stone he could see; obviously no human hands had made this place. To one side, a hot spring steamed invitingly next to another smaller tapestry: another room, perhaps a privy? The far side of the cavern hosted a bed piled high with furs and silks and a truly ludicrous amount of pillows. 

The dragon watched him with its great moon-pale eyes, then, with a flick that might almost be self-satisfied, curled its tail about its feet. Unnervingly, it didn't seem to blink.

Dimitri swallowed. "Ah." How did one address a dragon? "May I ask your name?"

' _I am the Fell Star,_ ' said the dragon. Its voice rang in his head, low and deep as stone sliding upon stone, or the calving of a glacier he had seen once in Gautier: unmistakably ancient and unspeakably inhuman. ' _I walk in the dark spaces between worlds, and hear the prayers of those who gaze upon me. I have heard your prayer._ ' It paused, looked Dimitri up and down, and then said, _'You may call me Byleth.'_

"'My prayer?'" Dimitri echoed. He’d hoped for an end to tensions with Almyra and Adrestia, as he always did each night, a productive sowing season for his people with the advent of spring, but-

_‘Yes,'_ said Byleth, rising onto all fours. Muscle swelled and rolled beneath the glimmering scales of its limbs as it began to pace, to circle him with its great eyes fixed upon him, its tail lashing. The wicked curved claws, bone-pale and glittering, ticked upon the stone with a chime of bells, unreal all over again.

Dimitri turned with it to keep its vicious fanged mouth in his sight, keeping his motions slow and smooth. He’d never been hunted before, was coming to find he didn’t like the cold certainty of the dragon’s gaze.

Byleth’s jaws opened as it lowered its head to Dimitri’s height. The petrichor scent of its breath filled the cavern. A great forked tongue unfurled to taste the air between them, and it took all Dimitri had to not back away further.

“I fail to see,” Dimitri said, somehow pleased with himself at how steady his voice was, “how kidnapping me grants any of my wishes.” 

‘ _You stood at your window and gazed upon the Fell Star,_ ’ said Byleth, ‘ _with a satisfied lover in your bed, and yet you-_ ’ it continued relentlessly as Dimitri choked on an indrawn breath, _‘you were unsatisfied. Aching with it.’_

What-?

_‘Aching,’_ said Byleth, and its voice grew low with terrible satisfaction, ‘ _for you wish, more than anything, to be pleasured until it overwhelms you, until you are no king at all, until all the cares in your mind have been driven away. To be held down and made to take it, and yet every human lover Fodlan offers you can never have hope of pinning you. Can never match your need._ ’

The dragon circled closer where Dimitri stood frozen, rooted to the floor, and between one step and the next it melted into mist, reformed into a curvy woman whose bare skin shone like the stars. ‘ _What do you desire? What shape would please you?_ ’ Another step, and flesh flowed and remade itself into a young man with the same great pale eyes. ‘ _I am here, Dimitri Alexandre Blaiddyd, king among kings, to grant your wish._ ’ Now the dragon stood before him again, its reptilian face at a height with his own, the great sweep of its horns just brushing the ceiling. It overwhelmed his senses with its bulk, its scent, every particle of him aware of the strange warmth of its body and the closeness of its flickering forked tongue.

“I…” he said, and lapsed into silence. Byleth was correct, though Dimitri could not recall ever consciously voicing such a wish. Though considering they were a dragon, or a star in dragon form, Dimitri couldn't spend too much time wondering how they knew that. He took few lovers, each carefully selected, and every single one of them had asked for him to be the aggressor. Whether it was due to his status, or his strength, or something else, he never asked and was never told; instead, he devoted himself to their wishes, to making sure no one left his bed unsatisfied. Except him.

"You could do such a thing?"

Byleth scoffed. Its tail flicked. ' _There are few things I cannot do._ '

Dimitri swallowed. There was something beautiful to the lines of the dragon's body and the strange glow of its eyes, and the terrible strength of its limbs seemed more convincing of his submission than any human form. But-

"Is there a form most comfortable for you?"

The light Byleth emanated dimmed, then flared even brighter until it overwhelmed the oil lamps. The dragon leaned closer, nudged him with its muzzle until he dared to rest a trembling hand on its skin: warm and humming with magic. ' _How terribly sweet of you, Dimitri,_ ' Byleth said, and its voice sang with surprised gratitude and lust, ' _but again, you concern yourself too much with the needs of others. I am here, my treasure, for you._ ' 

Byleth pushed him backwards onto the bed, where he fell among the obscene piles of pillows and silks, and regarded him with satisfaction. ' _You look beautiful among my things. Now._ ' It stalked closer, wings flicking open then closed, and shrank just a bit, until it no longer dwarfed the bedframe. One clawed forefoot, than the other, slammed onto the mattress and sent nearby pillows flying. ' _Strip so I may have you. My understanding of humans is that they value their clothes._ ' It paused, thoughtful. ' _Though the ones I took all these things from spent most of their time unclothed._ '

Dimitri stopped with his shirt halfway over his head. Byleth had invaded a house of ill repute, just to grant his wish-

He would simply have to compensate them later for the trouble, that was all. The shirt managed to escape his grip unscathed, and he tossed it aside, then met Byleth's gaze unflinchingly. 

One forefoot rose into the air. A claw flicked out, and with delicacy so fine Dimitri's chest ached with it, traced a single line from the waistband of his trousers to one of his nipples, pebbling in the cool air. 

_'Lovely thing,_ ' Byleth said, low and greedy, and flicked the end of its claw against his nipple.

A startled cry broke from his lips, his hips surging from the bed, and then Byleth's other foot pressed into the shuddering plane of his belly and held him there, not unkind, not unduly heavy, but inexorable. He might as well have tried to push a mountain off of him, and that-

That knowledge that he was held, caught, really and truly pinned-

Had his cock leaping in his trousers, his head dizzy with a sudden surge of arousal.

_'Trousers_ ,' Byleth said, and the weight on his belly lessened enough for him to squirm out of the offending garment. Byleth, either aware of its limitations or amused by him, didn't help, its gaze fixed on where it traced slow spirals about his nipple. 

Then, bared to the beast's avid gaze, Dimitri fell back against the mattress. He let his hands fall to his sides, and breathed. His cock, already wet at the tip, curved upwards and just missed the inside of Byleth's massive forearm.

' _So obedient,_ ' Byleth crooned, its attention near-tangible on every inch of him, from his flushed face to his thighs, spread lewdly for Byleth's perusal. ' _Lovely and willing and so_ helpless-' 

At that word Dimitri arched up against the dragon's grip with a moan, all his strength useless, and Byleth's tongue darted out to flick against his untouched nipple.

"Byleth-" the dragon's tongue was hot as the rest of it, but flexible and strong. It wrapped about his nipple and squeezed, and Dimitri choked on his words, drew another hitching breath as he tried to twist into the pressure. 

_'Yes_ ,' Byleth said, and now there was true greed in its tone, ' _cry out for me, my little prize_.' It spread its forepaw across his chest, held him still, and shifted the foot spanning his belly onto the mattress. His cock, untouched, stirred by the wind of its passing, leaped.

_'Ah_ ,' Byleth said. Its tongue slipped down Dimitri's chest, into the valley of his belly, darted to lap up the first fallen beads of precome in the trail of blond hair. ' _So sweet, Dimitri. So giving, letting me have you, small as you are._ ' Its clawed hand prickled at the sides of his chest, the fine scales of its palm tugging and twisting at his nipples until he tried to bow up into the touch, got nowhere-

Light exploded behind his eye as Byleth coiled its tongue about his straining cock. It was- it was _filthy_ , in the best way it could be, the dragon's tongue slick, saliva trickling down to wet his balls, his hole, hot and pulsing, wrapping him from root to tip and squeezing at him like- like a _cunt_ , almost, and oh-

"Byleth, Byleth-"

_'Very good,_ ' Byleth purred, and its eyes burned. Another careful twist and curl of its tongue, pressure rippling up the length of his cock in a milking wave he was helpless to resist-

He shuddered through climax, helpless to stop himself from crying out and thrashing against the weight of Byleth’s body, and yet Byleth remained, unmoved, its great eyes taking in every twitch and hiccuped cry, its desire unrelenting. 

He fell back against the bed as the last aftershocks rolled through him, his chest heaving beneath Byleth’s grip. Then twitched, biting back a whine, as Byleth’s tongue slipped off his cock and flicked back into its mouth.

‘ _Hm._ ’ Byleth tilted its head. ‘ _That was good, I think._ ’

“Yes,” Dimitri managed, and got one elbow underneath him to lean up, before the world spun as the dragon effortlessly flipped him onto his stomach. ‘ _What the-_ ’

A solid forepaw spread across his shoulders and forced him down to the mattress, and _oh_ , that must be- that must be what his strength felt like to others. He shuddered against the sudden spike of pleasure, and Byleth, sensing it, murmured,

‘ _You like that. How small you are beneath me. How weak. How I can do anything_ -’ and it pushed his knees wide so he was exposed, as he had never been, his cock and balls hanging in the chill air, his hole on _display_ -

‘ _So tiny,_ ’ Byleth mused, and its tongue dragged from the tip of his aching cock to the sudden emptiness of his hole, and lingered there, pushing against him while he strained against it. ‘ _Here?’_

He intended to answer, he really did, but Byleth knew him, and without a pause it licked him open, licked _into_ him, and Dimitri clawed at the sheets and moaned, loud, shameless. Not a cock, not at all, too wet and thick and muscular for it, and yet- 

His thighs shook, his knees skidding in the sheets, and before he could buckle Byleth caught him about the waist and held him, rumbling an amused, ‘ _Sensitive, are we?_ ’ Its tongue twisted deeper, and while it didn’t grind or thrust, it filled him to the brim until he could hardly stand the pressure, the pleasure of it. Byleth worked at his prostate, lashed at it until he shouted, until his cock spilled across the sheets.

“Ah, hold-”

But Byleth knew him, knew him better than he knew himself, and didn’t halt: only kept licking, delving into him, working him, until he whimpered, hands fisted in the bedclothes, hips shuddering where Byleth held him pierced. He pitched over the edge into another climax, so intense and dragging and deep he couldn’t make a sound, his breath caught in his chest, the pleasure so sharp and bright it bordered pain.

Byleth let him go, left him empty, and he collapsed to the mattress with a shaking moan. Whatever tension he carried in his body was long emptied, every limb lax and heavy. A hundred Adrestian warriors could have poured into the cave and he would be utterly useless, no king or defender at all. Goddess. Byleth truly was determined.

Petrichor breath stirred over the back of his neck, ruffled his hair. ‘ _You can give me another_ ,’ said Byleth, certain as the tides. ‘ _I haven’t fulfilled you yet.’_

Dimitri cracked open his eye to find Byleth’s expressionless face above him. If dragons could look smug, this one did. 

What more-

Oh. His body felt _empty_ , opened by the dragon’s tongue and still open, the cool air of the cave drawing attention to the sensitive nerves of his entrance. Could he be fuller?

‘ _Yes_ ,’ said Byleth, and its forelimbs came onto the bed, settled onto the mattress beside Dimitri’s shoulders, caging him in beneath its warmth and weight. Caging him in like- like a _beast_ , something to be _mounted_ , and at that Dimitri’s cock filled again. His hips lifted into the air in silent offering.

‘ _Lovely treasure_ ,’ said Byleth, its tongue coiling about his throat, drawing his head up, relentless. ‘ _Now._ ’

The breach of Byleth’s cock - for of course, Dimitri thought, half-delirious, Byleth could have whatever it wished, whatever it thought would bring Dimitri pleasure - was a slick, smooth glide, terribly easy, and yet-

Yet it spread him _wide_ , wider than he’d ever been in his _life_ , left him scrabbling at the sheets, the weight of it within him shoving the breath from him in a long wail.

‘ _So sweet_ ,’ Byleth purred above him. ‘ _Your body clutches at mine like a fist, like this is what you were made for_.’ It tensed, then drew back, the contours of its cock dragging at him and sparking more fires beneath his skin. ‘ _Made to take my cock. Made to be my concubine._ ’

“Byleth,” he managed, was all he could say, his racing thoughts quieted, his head empty of anything but the relentless overwhelming pleasure. And then he shuddered, cried out again as something wrapped about his cock and squeezed.

Byleth’s tail, coaxing still more from him.

Then Byleth thrust, and Dimitri howled. The dragon fucked him steadily, smoothly, its claws prickling at his hands, its cock so hot, so huge, every stroke dragging and grinding and working at his prostate until the last little dregs of come spilled forth, until he wept with the overwhelming ache of it. It filled him until he could hardly contain it, until he went limp and hung from Byleth’s tongue, from the hot slippery bar of its cock.

‘ _Delicious, my Dimitri_. _So good_.’

“Byleth,” Dimitri begged, too overwhelmed, oversensitive, his body rocking with each deep thrust, each steady grind and push forcing yet more pleasure from him. How could his body contain this much desire? “Oh, Byleth- please - in me-” he’d never thought of that, never _wanted_ that, but he wanted to be good, wanted to know that-

Byleth’s tongue uncoiled from around him. Its massive jaws closed carefully about his shoulders, his neck, savage teeth pricking at his skin, and even that was good. The scent of flame, petrichor, starlight suffused his senses. ‘ _Of course, my cherished one._ ’ 

Heat spilled within him, filling him up, and he cried out, a hoarse wail, and collapsed to the mattress. Byleth’s cock slipped from him, and the dragon’s come, hot, pearlescent, rolled in filthy strings down his thighs, over his balls, Dimitri possessed and taken and every inch adored.

Byleth followed him down, the last thing he recalled the glow of their eyes, the pleased hum of their voice as they said, ‘ _Sleep now, my beloved._ ’

* * *

“Your Majesty?”

Dimitri forced down the uncharitable thoughts in his head before he turned to Dedue.

“Yes, Dedue.”

He couldn’t be surprised that his vassal had hardly left him alone in the month since Sylvain and Ingrid had found him asleep in a village at the foot of the mountains. Nor was he surprised, if not a little irritated, that he could not bring himself to try to sleep with any of his former lovers; it seemed pointless to do so after such an experience as the one he’d had with Byleth. Not, of course, that he could say anything about it; he’d managed to fob off inquiries with the excuse that his mind had been wiped clean with magic.

“Another scholar has come to offer their services,” Dedue said. The slight wrinkle between his eyebrows told well what he thought of the many dubious experts who’d come offering their aid in hunting dragons. “This one seems to possess some knowledge, at least.”

“How so?” Dimitri fell into step beside Dedue as they entered the receiving room. “They aren’t offering me more potions to make me disgusting to reptiles, are they?”

“I think,” said a familiar voice, “no one could make you disgusting, Your Majesty.” 

What-?

The slim figure standing by the fire turned, and raised hands that shone like starlight to pull down their hood. 

A sudden sharp pang of joy rippled across Dimitri's skin as Byleth’s mouth twitched into a faint smile, and their words rang again in his mind.

‘ _Hello, beloved._ ’

**Author's Note:**

> Comments and criticism are adored. Follow me on Twitter at 'carthageburning' if you'd like!


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